绥阳双河洞国家地质公园边界优化

Optimization of the Boundary of Shuanghe Cave National Geopark in Suiyang County

双河洞是世界上最长的白云岩洞系,它构成了绥阳双河洞国家地质公园的主体。随着探测长度的持续增长,现行园区边界已不能满足保护与管理的需求。以双河洞空间分布为参考,运用ArcGIS水文与空间分析工具对池武溪流域及周边数字高程模型(digital elevation model,DEM)数据进行数字河网提取、地表流域分割,并综合考虑自然与人文因素,得到如下认识:①园区1∶5万DEM精度下设定1000 m^(2)的汇流累积量阈值模拟出的数字水系与真实水系一致性高;②双河洞系统跨越池武溪地表分水岭,直观反映了地表-地下分水岭不重合的现象;③双河洞系统自2018年就已超越现行地质公园边界以及县级行政区界线,核心地质遗迹保护与管理存在真空地带,园区边界优化调整迫在眉睫;④园区边界应结合双河洞系统发育界限预判为考量适时进行动态调整,并提出了初步的优化定界方案;⑤未来应加强双河洞区域的示踪试验,更加明确地下分水岭范围,以更加科学、完整地划定园区边界。

Shuanghe Cave is the longest dolomite cave system in the world,which constitutes the main body of Shuanghe Cave National Geopark in Suiyang County.With the continuous growth of survey length,the current Geopark boundary can no longer meet the needs of protection and management.Taking the spatial distribution of Shuanghe Cave as a reference,the hydrological and spatial ana-lysis tools from ArcGIS software was used to extract the digital river network and divide the surface basin from the digital elevation model data(DEM)of Chiwuxi Basin and its surrounding areas,and comprehensively considering the natural and human factors,the following understandings are form.The digital water system simulated by 1000 m^(2) concentration cumulant threshold with 1∶50000 DEM accuracy is highly consistent with the real water system.The Shuanghe Cave system crosses the surface watershed of Chiwuxi,which directly reflects the phenomenon that the surface underground watershed does not coincide.The Shuanghe Cave system has exceeded the boun-dary of the current Geopark and county-level administrative region since 2018.There is a vacuum in the protection and management of core geological relics,and the optimization and adjustment of the Geopark boundary is imminent.The boundary of the Geopark should be dynamically adjusted in consideration of the prediction of the development boundary of Shuanghe Cave system,and a preliminary optimization and demarcation scheme is proposed.The tracing test of Shuanghe Cave area should be strengthened in the future,and the scope of underground watershed should be more clear,so as to delimit the Geopark boundary more scientifically and completely.